The present invention relates to analog to digital (A to D) converters and methods. More particularly, the present invention relates to A to D converters and methods in which a plurality of inputs are provided which may be selectively grounded, left floating or tied to an applied voltage to supply various operational voltage ranges for the A to D converter.
Previously there has been disclosed an A to D converter which provided more than one operating range by means of two separate power supplies. By selectively applying an input voltage to either of two input terminals provided while digitally switching the second of the two power supplies, bipolar and unipolar input ranges could be provided. However, the use of the second switched current source with its concomitant digital switching has disadvantages. Moreover, the number of operating ranges available to an A to D converter as previously disclosed has been limited.
It is therefore an object of the present invention to provide an improved input ranging divider and method for an analog to digital converter.
It is still further an object of the present invention to provide an improved input ranging divider and method for an analog to digital converter which requires only a single power supply, obviating its digital switching, yet provides operational ranges above and below supply voltage and of the same and opposite polarity.
It is still further an object of the present invention to provide an improved input ranging divider and method for an analog to digital converter which provides a wide number of diverse operational ranges utilizing only a small number of device pins.